This has proven to be just as effective at preventing influenza in mice as intramuscular, hypodermic flu immunisation.

The team of researchers believe that the microneedle skin-patch method of delivering the flu vaccine might one day be used to vaccinate people against influenza.

The patches used in their experiments contained an array of stainless-steel microneedles coated with an inactivated influenza virus. The patches were pressed manually into the skin and, after a few minutes, the vaccine coating dissolved off within the skin.

The coated microneedle immunisations were compared to conventional intramuscular hypodermic injections at the same dose in another group of mice.

The researchers found that the microneedle vaccinations induced strong immune responses against the influenza virus that were comparable to immune responses induced by the intramuscular, hypodermic immunisations.

One month after vaccination, the researchers infected both groups of mice with a high dose of the influenza virus. While all the mice in a control group of unvaccinated mice died of influenza, all the mice in both the hypodermic and the microneedle groups survived.

‘Our findings show that microneedle patches are just as effective at protecting against influenza as conventional hypodermic immunisations,’ said Dr Richard Compans, Emory’s professor of microbiology and immunology.

Image shows an array of microneedles against a microscope image

The project team plans future immunisation studies in other animals, including guinea pigs or ferrets, before studying humans. Additionally, more studies are needed to determine the minimum vaccine dose needed for full protection.